1. Field of the Invention
This invention relates to an assembly for preforming a number of wires being helically wound about a hose and, more specifically, to such an assembly that can readily accommodate a predetermined number of wires and hoses of a predetermined size.
2. Description of the Invention
It is desirable in the production of high pressure hoses to provide armouring consisting of continuous windings of permanently deformable wires. The high pressure hose may include an inner hose, several layers of armouring which are separated by protective tape, and an outer protective covering. The several layers of armouring are usually in the form of pairs of windings in opposite directions to counterbalance any twisting or bending effect that winding in only one direction might impart to the hose.
A number of means have heretofore been employed to wind a plurality of wires on the inner hose by relative rotation of the respective sources of the wires about the hose. Longitudinally advancing the hose with respect to the sources of the wires continuously presents an unwrapped region of the hose at which the windings may be formed. It has been found that the winding can be accomplished by the prescribed relative movement and that whether the sources of the wire or the hose should be fixed or moving is generally determined by other considerations other than the specific act of forming the windings of the hose.
However, it has long been recognized that simple relative movement of the wire sources and the hose will not insure that the wire will be satisfactorily retained on the hose. The wire which is utilized for armouring is usually relatively resilient and tends to resist the required change in shape from that related to its source to that which is desired for helical wrapping. Therefore, after simple winding, the wires retain a natural resistance to the helical shape, which, if unrestricted, will result in uncontrolled separation of the wire from the hose as a different helical shape, having a different pitch and diameter, is established. If the original helical shape of the wire is maintained during the remaining formation of the high pressure hose, the natural resistance of the wire will generate undesirable internal forces within the high pressure hose that reduce its overall strength and effectiveness.
In an effort to solve this problem, a number of defices have heretofore been utilized in winding machines to preform the wire so that its natural resilience will not be in opposition to the desired helical shape. The preforming devices, such as those disclosed in U.S. Pat. Nos. 3,183,583, 3,187,494, and 3,357,456, have generally included a predetermined number of wire-receiving holes and wire-guiding surfaces for reverse bending of the wire in a region of the wire remote from the point at which it is applied to the inner hose. It appears to have been considered desirable to provide a reversely bent characteristic to the wire at this remote region in anticipation of continued winding about the hose until the remote region is properly oriented with respect to the hose so that the established bend as reoriented will tend to coincide with the shape of the hose. Without having to specifically consider the merits of this reverse bending concept, it should be apparent that because of the essential reorientation of the wire, the location and degree of the reverse bending might vary greatly with hoses having different diameters. Further, if not properly adjusted, any preforming device that institutes a deliberate deformation of the wire at a location remote from the hose can, because of the relative rotation, result in the wire being applied to the hose at an orientation which not only fails to follow the shape of the hose but might even have added resistance to it.
The above-mentioned, wire-receiving holes of the prior preforming devices tend to provide the desirable function of properly and evenly spacing the wire about the periphery of the hose to insure side-by-side alignment during winding. A predetermined number of wire-receiving holes presupposes a predetermined number of wires if even spacing is to be maintained but the time required for initially setting up the winding machines utilizing preforming apparatus that includes these wire-receiving holes is largely determined by the time required for each wire to be threaded through its respective wire-receiving hole.
Accordingly, the preforming devices previously employed in wire wrapping machines have not been readily adaptable to quickly begin wire wrapping hoses even if the diameter of the hose and the number of wires to be used is predetermined.